随机飘动的泡泡

import javafx.geometry.Pos
import javafx.scene.canvas.Canvas
import javafx.scene.canvas.GraphicsContext
import javafx.scene.paint.Color
import javafx.scene.paint.Paint
import javafx.scene.shape.Circle
import javafx.scene.text.FontWeight
import tornadofx.*
import java.util.*
import kotlin.system.exitProcess

class AlgoApp : App(AlgoFrame::class, Styles::class) {
    override fun stop() {
        super.stop()
        // 退出进程，runAsync也一并退出
        exitProcess(0)
    }
}

class AlgoFrame : View("随机飘动的泡泡") {
    lateinit var cv: Canvas
    val R = 50.0
    var circles = mutableListOf<MyCircle>()
    override val root = borderpane {
        center = canvas(700.0, 300.0) {
            cv = this
            with(cv.graphicsContext2D) {
                strokeRect(0.0,0.0,cv.width,cv.height)
            }
        }
    }

    private fun runn(){
     runAsync {
            while (true) {
                render()
                AlgoVisHelper.pause(20)
                circles.forEach {
                    it.move(0,0,cv.width.toInt(),cv.height.toInt())
                }
            }
        }
    }

    private fun render() {
        repaint()
    }

    private fun repaint() {
        cv.graphicsContext2D.clearRect(0.0, 0.0, cv.width, cv.height)
        cv.graphicsContext2D.strokeRect(0.0,0.0,cv.width,cv.height)
        paintComponent(cv.graphicsContext2D)
    }

    private fun paintComponent(g: GraphicsContext) {
        g.fill = Color.RED
        g.stroke= Paint.valueOf("red")
        circles.forEach {
            g.strokeOval(it.centerX, it.centerY, it.radius, it.radius)
        }
    }

    init {
        circles = genCircles()
        paintComponent(cv.graphicsContext2D)
        runn()
    }

    private fun genCircles(): MutableList<MyCircle> {
        return (0..10).map {
            val x = Random().nextDouble() * (700 - 2 * R) + R
            val y = Random().nextDouble() * (300 - 2 * R) + R
            val vx = Random().nextDouble() * 11 - 5
            val vy = Random().nextDouble() * 11 - 5
            MyCircle(x, y, R, vx, vy)
        }.toMutableList()
    }

}

class MyCircle(var x: Double, var y: Double, var r: Double, var vx: Double, var vy: Double) : Circle(x, y, r) {
    fun move(minx: Int, miny: Int, maxx: Int, maxy: Int) {
        this.centerX += vx
        this.centerY += vy
        this.x += vx
        this.y += vy
        checkCollision(minx,miny,maxx,maxy)
    }

    private fun checkCollision(minx: Int, miny: Int, maxx: Int, maxy: Int) {
        if (x - r < minx) {
            x = r
            vx = -vx
        }
        if (x + r >= maxx) {
            x = maxx - r
            vx = -vx
        }
        if (y - r < miny) {
            y = r
            vy = -vy
        }
        if (y + r >= maxy) {
            y = maxy - r
            vy = -vy
        }
    }
}

class Styles : Stylesheet() {
    init {
        button {
            padding = box(10.px)
            alignment = Pos.CENTER
            backgroundColor += c("#DD7549")
            fontWeight = FontWeight.EXTRA_BOLD
            fontSize = 14.px

            and(hover) {
                backgroundColor += c("#A05434")
                textFill = Color.WHITE
            }
        }
        label {
            fontSize = 14.px
            textFill = Color.RED
        }
    }
}